/*
 * @Author: szx
 * @Date: 2021-12-21 15:45:09
 * @LastEditTime: 2021-12-21 15:49:28
 * @Description:
 * @FilePath: \leetcode\200-299\226\226.js
 */

function TreeNode(val, left, right) {
    this.val = val === undefined ? 0 : val;
    this.left = left === undefined ? null : left;
    this.right = right === undefined ? null : right;
}

/**
 * @param {TreeNode} root
 * @return {TreeNode}
 */
var invertTree = function (root) {
    if (!root) return root;
    [root.left, root.right] = [root.right, root.left];
    invertTree(root.left);
    invertTree(root.right);
    return root;
};
